Black plug

[ruppert22]

I know it means too rich....I've got 2003 400ex with a white bros
e-series slip on K&N filter w\outerwear Dyno Jet kit that i put a
160 jet in told me not to change pilot jet Any advice on what to do.

[2004TRX450R]

If you've been rideing it for awhile and took it out and it was black it really isn't telling you much of anything. When you start the bike cold and have the choke on it will be really rich and will make the plug black. Plus it could be rich in some areas and not in others and it can make the plug black. The ONLY way to tell is to do a plug chop by runing it WOT for a few seconds then hitting the kill switch and shutting her down and then check the plug. As for the pilot circuit just get it up to operateing temp and adjust the screw until it reaches the highest idle and that is where you want to be.